com.facebook.buck.java.ZipEntryJavaFileObject.java Source code

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Here is the source code for com.facebook.buck.java.ZipEntryJavaFileObject.java

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/*
 * Copyright 2012-present Facebook, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may
 * not use this file except in compliance with the License. You may obtain
 * a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */

package com.facebook.buck.java;

import com.google.common.base.Charsets;
import com.google.common.base.Preconditions;
import com.google.common.io.CharStreams;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;

import javax.annotation.concurrent.GuardedBy;
import javax.tools.JavaCompiler;
import javax.tools.JavaFileObject;
import javax.tools.SimpleJavaFileObject;

class ZipEntryJavaFileObject extends SimpleJavaFileObject {

    private final ZipFile zipFile;
    private final ZipEntry zipEntry;

    @GuardedBy("this")
    private String contents;

    public ZipEntryJavaFileObject(ZipFile zipFile, ZipEntry zipEntry) {
        super(createURIFromEntry(zipEntry), JavaFileObject.Kind.SOURCE);
        this.zipFile = Preconditions.checkNotNull(zipFile);
        this.zipEntry = Preconditions.checkNotNull(zipEntry);
    }

    /**
     * Creates a canonical URI that represents the {@link ZipEntry}. This URI starts with
     * {@code "string:///"} because {@link JavaCompiler} does not seem to tolerate URIs that start
     * with {@code "jar:///"}, even though that would be more appropriate.
     */
    private static URI createURIFromEntry(ZipEntry entry) {
        try {
            return new URI("string:///" + entry.getName());
        } catch (URISyntaxException e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * Returns the contents of the {@link ZipEntry} as a string. Ensures that the entry is read at
     * most once.
     */
    private synchronized String getContentsAsString() {
        if (contents != null) {
            return contents;
        }

        try (InputStream inputStream = zipFile.getInputStream(zipEntry)) {
            contents = CharStreams.toString(new InputStreamReader(inputStream, Charsets.UTF_8));
        } catch (IOException e) {
            throw new RuntimeException(e);
        }

        return contents;
    }

    @Override
    public CharSequence getCharContent(boolean ignoreEncodingErrors) {
        return getContentsAsString();
    }
}